Detailing the Security Risks In PDF Standard

crabel writes with this quote from the H Online: "At the 27th Chaos Communication Congress in Berlin security researcher Julia Wolf pointed out numerous, previously hardly known security problems in connection with Adobe's PDF standard. For instance, a PDF can reportedly contain a database scanner that becomes active and scans a network when the document is printed on a network printer. Wolf said that the document format is also full of other surprises. For example, it is reportedly possible to write PDFs which display different content in different operating systems, browsers or PDF readers — or even depending on a computer's language settings."

Agreed. This is an Adobe Reader problem

[Vandil X]

At the end of the article, it is revealed that the exploits are Adobe Reader problems that are going to be addressed starting with Adobe Reader 10. So people that do not use Adobe's Reader client to view PDFs are not at as much risk, depending on how their non-Adobe PDF-reader solution is configured.

Of course, we all know the vast majority of the world (especially corporate users) uses Windows, and thus, Adobe Reader, so the security problems mentioned in the article are a valid cause for general concern... But not a concern for the PDF format in general.

Re:Abomination

[Xugumad]

> Excuse me, but a document format used for storing printed documents on a system should represent the document as if it was printed when viewed again, _not_ suddenly switch the language or layout or whatever.

It sounds like what you want is PDF/A ( http://en.wikipedia.org/wiki/PDF/A [wikipedia.org] ), which restricts the PDF to a simple non-scripted document. The fact that PDF is almost solely used to produce printed documents doesn't mean that's the intent of the format. DjVu ( http://djvu.org/ [djvu.org] ) I believe would also be a good fit.

For example, we're looking at taking in student essays in PDF, attaching a form to the front that marks can be entered into, and the whole document returned to the submission system that then pulls the mark out (as opposed to having to track the mark independently of the material it applies to). I've seen presentations run from a PDF before. It would be a pity to lose these possibilities.

Re:Abomination

[Anonymous Coward]

So this higher level is going to have fully automated language translation to guarantee the precise meaning of the contract is the same in every language? I think anyone expecting a computer solution to that with current technology is going to be disappointed. If I send 20 text files, one in English, one in French, one in German etc. believe it or not I can still put different stuff in each.

The real problem I suspect here is that the reporting of what was said is not reflecting the actual problems perceived just listing some of the mechanism which have been/can be exploited. e.g. Saying that javascript can read and edit pdf documents, erm well javascript can read and edit html, graphics files etc. etc. So a computer language can read and maniupate the contents of computer files who would have thought.

Similarly the multi-language/OS stuff maybe a security issue if I taylor different "payloads" meaning my document appears fine where I can't exploit it and appears fine to me as the author but is evil elsewhere. People trust me, so me saying the document opens fine and is benign may help spread something. If the article reported more detail perhaps the issues at stake would be clearer.

Re:Abomination

[Anonymous Coward]

A recording of the presentation will soon appear here [ftp.ccc.de] and should answer your request for more details.

Re:Abomination

[TheRaven64]

Not exactly. A subset of PDF is almost identical to a subset of PostScript. A PDF file is a dictionary of objects. These can be in a variety of formats, including binary data which can contain images and so on. One of the formats is drawing commands. These can be written in an extended subset of PostScript, with the flow control primitives removed and a few other commands added. You can convert PostScript to PDF by executing the PostScript program and recording the trace through it (basically, unwind all of the loops, pick one branch in all of the conditionals) - the subset that controls drawing is the same in both.